In the prior art, by bending sheet metal, constituted from iron, aluminum or alloy thereof, in a predetermined shape, various products have been manufactured for use in a vehicle such as a motorcar, components, building materials, or furniture. As the bending method, for example, a roll forming method for continuously deforming an object, or press working by means of a press brake, may be possible.
As a method for bending a sheet metal, PLT 1 discloses a continuous manufacturing method, wherein a bent portion of a sheet material is locally heated and softened while the sheet material is moved, and then the sheet material is transmitted through rolls or a forming device.